/Engine/Source/Runtime/GeometryCore/Public/Spatial/SegmentTree3.h
This function tries to find the segment "hit" by the ray, where the definition of "hit" tries to balance distance from the ray origin (ie "close to eye") and distance from the hit segment (ie "on the line"). There is no correct way to do this, currently the code uses a metric based on the opening angle between ray and segment points.
void FindNearestVisibleSegmentHitByRayInternal ( int BoxIndex, const FRay3d & Ray, [TFunctionRef](API\Runtime\Core\GenericPlatform\TFunctionRef)< bool(int32, const FVector3d &, const FVector3d &)> WithinToleranceCheck, int & NearSegmentIdx, [FRayNearestSegmentInfo](API\Runtime\GeometryCore\Spatial\FSegmentTree3\FRayNearestSegmentInfo) & NearestInfo, const [IMeshSpatial::FQueryOptions](API\Runtime\GeometryCore\Spatial\IMeshSpatial\FQueryOptions) & Options ) const